Effect of non-condensable gases on the flow of water and steam in geothermal wells

Abstract

This paper describes a study on the effects of non-condensable gases (IG) represented by carbon dioxide, on the numerically simulated flow characteristics of water and steam in geothermal wells. The presence of IG affects the thermodynamic conditions dominating the flow process in the well or within the reservoir. Most geothermal fluids are generally composed of a mixture of water and steam and substantial amounts of IG and salts. Gas concentrations often vary considerably in a geothermal field. They can be useful tools for inferring flow patterns both in wells and within geothermal reservoirs. Geothermal fluids also carry a high content of dissolved solids and salts. Well and pipeline flow simulation of geothermal fluids requires that thermodynamic and transport properties be properly accounted for. Several equations and correlations were used to estimate the properties of the H2O-CO2 mixture during simulations.The results revealed that the presence of CO2 affects significantly the location of the flashing point in the well and the amount of steam produced.

Keywords

• Geothermal wells
• production characteristics
• incondensible gases
• flow simulation
• two-phase flow